Fluid Mechanics and Energetics

Denis Sipp

Scientific Director of the
Fluid. Mechanics and Energetics domain

MFE in brief

Scientific officers

Adrien Langenais' thesis “Adaptation of aeroacoustic methods and tools for interacting jets in the context of space launchers” (with CNES)

HiLiNo (High Lift Noise) Generate a database to better understand the physics of noise generation and validate numerical simulation methods for the noise of civil aircraft high lift systems, a major component of approach noise.

CIGALE, MOTUS A better understanding of the annoyance or noise generated by aircraft. This listening room will make it possible to link the annoyance felt when an aircraft flies over to individual and societal factors, or to evaluate the annoyance generated by different noise reduction technologies, for example.

InnoSTAT (Innovative Stator) Reduce the noise of civil aircraft engines by reducing the interaction between turbulence and the leading edge of the fan stator. The shape of the serrations is optimized using CAA (Computational AeroAcoustics) calculations.

Hypersonic flows

DMPE Julien Labaune, Ysolde Prévereaud  (@onera.fr)

• Cold and hot hypersonics
• Transition, turbulence and heat flux modeling
• Hyperenthalpic flows
• Chemical and vibrational imbalance effects
• Rarefied gas effects
• Application to atmospheric re-entry and super-ramjet

DAAA Mathieu Lugrin, Sylvain Morilhat  (@onera.fr).

• Cold hypersonics
• Transition
• Turbulence
• Modeling
• Heat flux
• Shock drag
• Viscous drag
• Bottom drag
• Control surfaces

Example

MOPPHYP Modeling of physical phenomena related to hypersonics Advance numerical, theoretical and experimental tools: simulation of the high Mach number transition, modeling of parietal turbulence outside adiabatic equilibrium, understanding the dynamics of shock wave/boundary layer interactions.

• Subsonic, transonic and supersonic regimes
• Laminar/turbulent transition
• Transitional bulbs
• Transition models
• Linear and non-linear stability
• Shock/boundary layer interaction
• Buffeting
• 2D and 3D detachment
• Stall
• Pumping
• Corner flows
• Low Reynolds flows
• RANS and hybrid RANS-LES turbulence models
• Wall laws
• Vortex flows and wakes
• Afterbodies
• RANS and hybrid RANS-LES turbulence models
• Reconstruction of turbulent fluctuations

EASA (Aero-thermo-chemical evolution in aircraft wakes, ONERA project). Challenges addressed: control of wakes and contrails; extension of the simulation distance downstream of the aircraft by HPC optimization and mesh optimization techniques, with the ambition of bridging the gap between the fields dealt with by aerodynamicists and climatologists; optimization of aircraft geometry based on multiple criteria, including vortex wake evolution and environmental impact.

Data-driven modelisation

[CNU* 60] [CoCNRS* 10]

DAAA Samir Beneddine, Vincent Mons (@onera.fr).

• Uncertainty propagation
• Learning techniques
• Mathematical input/output reduced models
• Fusion, Data Assimilation
• POD - DMD - SVD
• Drag extraction
• Detection and parametric identification of structural non-linearities
• Acoustic source identification
• Noise propagation
• Acoustic detection of moving objects
• Non-linear dynamics applied to aircraft
• Flight dynamics in inhomogeneous and unsteady environments

Experimental methodes for aerodynamics

DAAA François Nicolas, Geoffrey Tanguy (@onera.fr)

• Optical surface metrology (TIR, MDM, PSP, TSP, friction, etc.)
• Optical field metrology (PIV, PIV3D, Holography, BOS)
• New sensors
• Big data processing
• Control of non-dimensional parameters, uncertainties and measurement noise
• Improvement of ground testing facilities

Example

 

CARACAL - Aeroelastic tailoring of flexible wing to alleviate gust load. Thanks to unsteady pressure-sensitive paint (PSP) and model deformation measurements (MDM) the aeroelastic response of the structure has been characterized. This wind tunnel test campaign will be used to validate the design of future composite structures

 

 

Wall-bounded flow dynamics

[CNU 60] [CoCNRS 10]

DMPE  François Chedevergne, Jean-Philippe Brazier  (@onera.fr)

• Subsonic, transonic and supersonic regimes
• Laminar-turbulent transition
• Transitional separation bubbles
• Receptivity to roughness, acoustic excitations and external turbulence
• Transition models
• Linear and non-linear stability
• Shock-boundary layer interaction
• Buffet
• 2D, 3D separation
• Stall
• Surge/Buzz
• Corner flows
• Low Reynolds flows
• RANS and hybrid RANS-LES turbulence models
• Wall laws
• Reconstruction of turbulent fluctuations

Example

FROTTEMENT Better physical understanding of viscous drag generation; improved friction measurement techniques and ways to implement them in ONERA wind tunnels; improved turbulent friction modeling, new models that can be implemented in major ONERA industrial codes.

ROOT Modeling of the dynamic and thermal effects of wall roughness Creation of experimental and numerical databases on reference cases, development of a Double Averaged Navier-Stokes formulation based on the notion of discrete elements, which can be implemented in ONERA's major codes..

 

Exploitation of experimental and numerical data

DMPE David Donjat, Nicolas Fdida (@onera.fr)

• Signal processing
• Data fusion
• Data assimilation
• Inverse methods
• Quantification and propagation of uncertainties
• Reduced models
• Segmentation in image processing
• Learning techniques
• POD, sPOD, DMD
• Multi-scale analysis

COMETH Oxygen-methane cryogenic combustion In the field of liquid propulsion, provide additional building blocks for modeling and understanding, with a view to simulating the ignition and ramp-up of a rocket engine in the longer term. Provide support during the design phase and in the event of an incident encountered by industry.

EMPIRE Study and measurement of particles from jet engines Systematic evaluation of the impact of fuel composition on emitted or induced particles (volatile and non-volatile), carried out on a device replacing an aircraft engine

SUNSET2 Studies on scling effects due to ice In collaboration with NASA, improving ice accretion codes (ONERA's IGLOO3D) and assessing the accuracy required on 3D ice shapes to predict performance degradations on large swept wings.

Numerical work was carried out (improvement and benchmarking of the IGLOO3D code, performance degradation calculations with elsA, using the classic body-fitted method or immersed boundaries (IBM)), as well as tests in the F1 wind tunnel.

ONERA's icing wind tunnel has delivered its first results in the H2020 ICE-GENESIS project to study the accretion of Supercooled Large Droplets (SLD) onto the surfaces of aeronautical structures. These large drops are present in freezing  or freezing rain and constitute a risk for transport aircraft, the control of which is essential in the aircraft certification process. This initial database will enable current icing models to be extended.

Simulations of ice accretion on a propeller were carried out during the Flying Whales project to estimate the effects of ice on airship components. This figure illustrates an accretion calculation on a 4m diameter propeller rotating at 800 rpm. Three solvers were involved: elsA for aerodynamics, SPIREE for supercooled water droplet trajectories and FILM for water runback and ice accretion on the propeller.

The modeling of ice fracture on surfaces protected against ice is being carried out as part of the TRICEPS project - a cooperation between researchers in the fields of energetics and materials/structures. An experiment to validate the simulation tools was done in 2022 in ONERA's icing wind tunnel. Highly controlled mechanical stresses will be applied to a realistic ice block geometry to induce its fracture. The experiment has been dimensioned using simulations with the Z-set code (figure) - a first for this type of costly 3D calculation.

DESORBITER Experimental studies and modeling of the degradation of space debris during atmospheric re-entry To better understand, model and simulate the thermomechanical degradation of space debris during re-entry, and to overcome scientific and technical obstacles in aerothermodynamics, thermodynamics, structural mechanics and fluid-structure coupling.

Jet dynamics

DMPE François Vuillot, Adrien Langenais (@onera.fr)

This theme covers a large number of activities aimed at a better understanding of the development and possible interactions of jets used in propulsion.

Areas of research

• Multi-species, reactive, often multiphase and essentially supersonic non-adapted jets, in laminar and turbulent, continuous and rarefied regimes
• Interacting jets (clusters, impacts, crossflow, recirculation, backflow and toss-back)
• Experimental aspects: set-ups, measurement methods and advanced optical diagnostics
• Numerical aspects: modelling (turbulence, combustion, two-phase, radiation) and simulations (multi-physics, RANS, LES, DNS, DSMC, HPC, couplings)
• Translated with DeepL.com (free version)

Exemples

>> The acoustic environment on space launcher launch pads

Impact jet, LP13 launch, SITADEL project, DMPE/LPF - CFM 2023

Various impact jet situations (acoustic, thermal, mechanical and multi-fluid aspects)

ONERA CEDRE numerical simulation of the blast wave of a configuration studied in the preliminary design for Ariane 6 (CNES)

Liquid jets injected into a gaseous medium

Water jet discharging into an atmosphere at rest and atomisation. CEDRE calculation,
thesis V. Morin, 2023

>> Aerothermochemical environment at the base of space launchers and missiles

Design of the ADiJe study set-up (supersonic, hot, two-phase jet), DAMYSOS project

Optical and electromagnetic signatures of missile jets

Calculation of the electromagnetic properties of the 2nd stage jet of the M-V space launcher (JAXA) at 85 km altitude - RANS simulation with the CEDRE code, SIMBA2 project..

Radio blackout due to space launcher and missile jets

Calculation of the expansion of a jet in a rarefied environment through a millimetre nozzle (DLR) - NS-DSMC coupled simulation with the CEDRE and SPARTA codes, SIMBA2 project